Cheating boyfriend (will be home soon)

Hi,to cut a long story short cause m pushed for time (hell be back soon): - Been together for 2 years, cheated on me previously. Promised he wouldn't again and I moved in with him (and his friends). Anyway I suspected something this morning... he shaven down there (which he never does) and was being suspicious on his phone. I go on his Facebook and there are messages to another girl which confirms he spent the night at this other girls house. (He lied and told me it was someone he knew). She even asks him 'why do you cheat on her?'... I don't know what to do. Im in turmoil. I live with him ffs, its a day after valentines day...

It's in us whether we'll cheat or not...circumstances don't come into to it....hence the old saying goes...'once a cheater, always a cheater'. You can't trust him. His disrespect for you will only drag you down. He can't respect you..he has none for himself. Why live your life with like this?